1) If it runs on my dime and my infrastructure I will optimize the hell out using most cleverly written Rust and what not and gloat about engineering prowess.
2) If it runs on users computers well then, we have carefully evaluated our strategic direction and come to conclusion that JS/TS/Electron option is the best way to go.
IMO -- it makes total sense within the existing Cloudflare tooling ecosystem.
Javascript is plenty fast, but only if it has enough time to JIT the code and can keep it JITed in memory. For long-running backed services, it's plenty fast, for browser things, it's the only option, but for the command line, it adds needless startup time.
Agents make this even worse because they don't have a "sense of time", so if they accidentally do something which causes startup time to increase dramatically, they won't feel it like a human dev would, and won't immediately start optimizing. Unless you have some specific benchmarks in CI that fail any PR which makes the code too slow, agents will just make things slower and slower.
Are there any languages doing something unique or are especially resilient in this respect?
i'd probably write it in rust and expose ts bindings tho.